System and method of monitoring an environmental parameter along a predetermined route

ABSTRACT

A monitoring system has a vehicle and a monitoring device. The vehicle is movable along a predetermined route, and the monitoring device is detachably mounted to the vehicle. The vehicle has a photonic device configured to read position information according to detection of a positioning tag positioned at a predetermined position along the predetermined route. The monitoring device has a sensor configured to monitor an environmental parameter and a controller communicatively coupled to the sensor and the photonic device. The controller is configured to record the monitored environmental parameter along the predetermined route and the position information.

TECHNICAL FIELD

The present disclosure relates to semiconductor manufacturing, and moreparticularly, to a system and method of monitoring an environmentalparameter along a predetermined route.

BACKGROUND

During manufacturing of semiconductor integrated circuits (ICs),semiconductor wafers are subjected to multiple processing steps atdifferent processing equipments. For example, to complete thefabrication of an IC chip, various steps of deposition, cleaning, ionimplantation, etching, and/or passivation steps are generally carriedout in different processing equipments. Therefore, fabricationfacilities generally include transportation systems such as an automatedmaterial handling system (AMHS) for transporting the semiconductorwafers among the processing equipments.

Further, in a fabrication facility, a carefully controlled environmentwhen transporting the semiconductor wafers is important due to thedelicate nature of the chips. Abnormalities in vibration, temperature,humidity, or level of contamination along the route of transportationincrease the risk of unexpected particles or features formed on thewafers and decrease the yield rate of the manufacturing process.Therefore, there is a need for monitoring one or more environmentalparameters when transporting the semiconductor wafers.

DESCRIPTION OF THE DRAWINGS

One or more embodiments are illustrated by way of example, and not bylimitation, in the figures of the accompanying drawings, whereinelements having the same reference numeral designations represent likeelements throughout and wherein:

FIG. 1A is a perspective view of a portion of a monitoring systemaccording to an embodiment;

FIG. 1B is a cross-sectional view of the monitoring system depicted inFIG. 1A;

FIG. 2 is a diagram of exemplary predetermined routes and positioningtags according to an embodiment;

FIG. 3 is a system diagram of the monitoring system for monitoring anenvironmental parameter along a predetermined route according to anembodiment;

FIG. 4 is a flow chart of a process for monitoring an environmentalparameter according to an embodiment;

FIG. 5A is a chart of a recorded environmental parameter according to anembodiment;

FIG. 5B is a chart of the recorded environmental parameter and overlaidrecorded position information according to an embodiment; and

FIG. 6 is a diagram of an exemplary visualized presentation ofpredetermined routes with dots depicted to identify positions ofabnormality.

DETAILED DESCRIPTION

FIG. 1A depicts a portion of a monitoring system 100 for monitoring anenvironmental parameter along a predetermined route according to anembodiment. A track 102 is positioned to define the predetermined routealong which the monitoring system 100 is movable. The monitoring system100 comprises a vehicle 110 configured to move along track 102 and amonitoring device 120 detachably mounted to vehicle 110 and configuredto monitor an environmental parameter. In some embodiments, themonitoring system 100 is an AMHS adapted to perform the monitoringfunction. In some embodiments, the monitoring system 100 monitors one ormore environmental parameters including vibration, temperature,humidity, or level of contamination along the route of transportation,or any combination thereof.

FIG. 1B is a cross-sectional view as seen if looking at (imaginary)plane A of the monitoring system 100 depicted in FIG. 1A. In at leastone embodiment, track 102 is a guide rail mounted to a ceiling 104 in afabrication facility, and vehicle 110 is movably mounted to the guiderail. In some other embodiments, track 102 comprises a rail, a magneticstrip, a conveyor, or a combination thereof. Depending on the type oftrack and vehicle, in some embodiments, the track is mounted on a flooror an elevated structure. Vehicle 110 is configured to carry a payloadand move along the track. The payload, in some exemplary applications,comprises a Front Opening Unified Pod (FOUP) designed to hold one ormore semiconductor wafers. In at least one embodiment, the payload ismonitoring device 120.

Further, a positioning tag 122 is positioned at a predetermined positionalong the predetermined route and vehicle 110 comprises a photonicdevice 124 configured to read position information from positioning tag122 according to detection of positioning tag 122. In some embodiment,positioning tag 122 is positioned on or adjacent to the track 102. In atleast one embodiment, positioning tag 122 comprises a barcode and thephotonic device 124 is a barcode reader for detecting the barcode on thepositioning tag 122. In some other embodiments, positioning tag 122comprises an optical feature such as a barcode, a text, a figure, or acombination thereof and photonic device 124 is configured to beresponsive to all or a portion of visible lights, infrared lights, orultraviolet lights, or any combination thereof, that it received eitherdirectly from a light source or by reflection.

FIG. 2 depicts an exemplary layout of predetermined routes andpositioning tags according to an embodiment. A plurality of positioningtags 202 a through 202 i similar to the positioning tag 122 (FIG. 1B)are positioned at a plurality of predetermined positions along theroutes or tracks 212 a through 212 f. In some embodiments, the positioninformation acquired by the vehicle 110 is sent to a traffic controlcenter for controlling the traffic on the tracks, i.e., the movement ofat least one vehicle 110 on the tracks. For example, at a specific timein at least one embodiment, there is more than one vehicle 110 mountedon and mobile along the tracks 212 a-212 f in order to transportsemiconductor wafers to different processing equipment in thefabrication facility. The traffic control center directs vehicles to acorresponding destination processing equipment while avoiding collisionsbetween the vehicles. Further, in order to monitor an environmentalparameter in the fabrication facility along the tracks 212 a-212 f, atleast one vehicle 110 carries a monitoring device 120 instead of one ormore FOUPs holding semiconductor wafers or other payload types. In someembodiments, the vehicle 110 with the monitoring device 120 moves alonga predetermined route for monitoring the environmental parameter alongthe predetermined route.

In some embodiments, on top of the positioning tags 202 a-202 inecessary for traffic control, more positioning tags are placed alongthe tracks 212 a-212 f at sections where higher spatial resolution formonitoring the environmental parameter is preferred. For example, in anembodiment in which the vibration of the vehicle 110 along the tracks212 a-212 f is monitored, more positioning tags are positioned atpositions where track assemblies are jointed, where there is a trackjunction, or where there is a curved track.

FIG. 3 depicts a system diagram of a monitoring system 300 formonitoring an environmental parameter along a predetermined routeaccording to an embodiment. Similar to the monitoring system 100 (FIGS.1A and 1B), the monitoring system 300 comprises a vehicle 310 configuredto move along the predetermined route and a monitoring device 330detachably mounted to the vehicle 310. In addition, in at least oneembodiment, the monitoring system 300 further comprises a log server 350configured to receive the recorded monitored environmental parameter andthe recorded position information from the monitoring device 330. Thelog server 350 comprises a display device 352 configured to display avisualized presentation of the predetermined route, the recordedmonitored environmental parameter, and/or the recorded positioninformation. In some embodiments, the log server 350 further comprises amicrocontroller 354 electrically coupled to the display device 352 tocontrol the operation of the display device 352 and a storage 356electrically coupled to the microcontroller 354 to store the recordedmonitored environmental parameter received from the monitoring device330.

The vehicle 310 is configured to transport the monitoring device 330 andmove along the predetermined route, such as a track 102 (FIG. 1B). Insome embodiments, vehicle 310 comprises a photonic device 312, acontroller 314 communicatively coupled to the photonic device 312, and acommunication module 316 communicatively coupled to the photonic device312 and the controller 314. The photonic device 312 reads positioninformation according to detection of a positioning tag positioned at apredetermined position along the route or track. The communicationmodule 316 transmits the position information to the monitoring device330.

In at least one embodiment, the controller 314 manages the operation ofthe photonic device 312 and the communication module 316. Further, insome embodiments, the controller 314 also controls a motor of thevehicle 310 in order to drive the vehicle 310 along the route or trackbased on a predetermined traffic control functionality programmed in astorage device of the vehicle 310 or instructions issued by a trafficcontrol center to the vehicle 310.

In at least one embodiment, the monitoring device 330 comprises a sensor332, a controller 334, a storage device 338, and a display 340. Thecontroller 334 is communicatively coupled to the sensor 332, the storagedevice 338, and the display 340 to manage the operation of themonitoring device 330. In some embodiments, the controller 334 comprisesa general-purpose microcontroller, a processor, or anapplication-specific integrated circuit (ASIC) and the storage device338 comprises a hard drive, a flash drive, a DRAM, an SRAM, or anapplicable storage device such as a computer readable medium storinginstructions for execution by the controller 334.

The sensor 332 monitors the environmental parameter. In at least oneembodiment, the sensor 332 is a vibration sensor for monitoring avibration along the route or track of the vehicle 310 to which themonitoring device 330 is attached. For example, in some embodiments, thesensor 332 is a tri-axial vibration sensing device. The tri-axialvibration sensing device continuously, or repetitively according to apreset timing pattern, monitors vibrations and decomposes them intox-axis, y-axis, and z-axis components. In some embodiments, the sensor332 is a vibration sensing device capable of recording vibrationsaccording to less or more than three axes. In some other embodiments,the sensor 332 is configured to detect vibration, temperature, humidity,contamination levels in the air, noise, bio-hazardous particles, or anycombination thereof. In at least one embodiment, the sensor 332 is acamera configured to acquire still images or video clips.

In some embodiments, the controller 334 records the monitoredenvironmental parameter and stores the parameter in the storage device338. For example, the controller 334 receives the vibration informationfrom the sensor 332 and records the vibration information in atime-based manner with a plurality of time tags along a time axis. Insome embodiments, each stored vibration data point is associated with atime tag. Further, in some embodiments, the controller 334 iscommunicatively coupled with the photonic device 312 throughcommunication module 336. In some embodiments, the controller 334receives the position information from the vehicle 310 and stores theposition information in the storage device 338. In at least oneembodiment, while recording the monitored environmental parameter andthe position information, the controller 334 also associates theposition information with at least one of the plurality of time tags.

The communication module 336 of monitoring device 330 communicates withthe communication module 316 of vehicle 310. In some embodiments,communication modules 316 and 336 are coupled in a wired manner. Forexample, when mounting the monitoring device 330 onto the vehicle 310,as depicted in FIG. 1B, the communication modules 316 and 336 areelectrically coupled through a USB connection, an IEEE-1394 connection,a RS-232 connection, an optical fiber, or another applicable connection,either serial or parallel. In some embodiments, communication module 316is electrically connected to a set of connecting pins, and communicationmodule 336 is electrically connected to a set of connecting pads, wherethe connecting pins and corresponding connecting pads form electricalcontacts with each other when the monitoring device 330 is mounted ontothe vehicle 310.

In yet some other embodiments, the communication modules 316 and 336 arecommunicatively coupled in a wireless manner. For example, in at leastone embodiment, the communication module 316 and the communicationmodule 336 are BLUETOOTH communication modules capable of communicatingwith each other according to a BLUETOOTH communication protocol. In someembodiments, the communication module 316 and the communication module336 are wireless LAN modules, infrared communication modules, lasertransceivers, or any applicable wireless communication modules accordingto industry protocols or proprietary protocols.

In some embodiments, a log server 350 comprising a display device 352configured to communicate with the monitoring device 330 in order toreceive the recorded monitored environmental parameter and the recordedposition information. In at least one embodiment, the monitoring device330 is removed from the vehicle 310 after being transported along apredetermined route by the vehicle 310, and then the log server 350 iscommunicatively coupled to the monitoring device 330 in a wired orwireless manner, such as the exemplary communication methods presentedabove for communication modules 316 and 336. In at least anotherembodiment, the log server 350 is communicatively coupled to themonitoring device 330 in a wireless manner and receives the recordedmonitored environmental parameter and position information while themonitoring device 330 remains mounted to and transported by the vehicle310.

The display device 352 displays the visualized presentation of themonitoring results received from the monitoring device 330. In someembodiments, the display device 352 is an LCD monitor. Further, in atleast one embodiment, the monitoring device 330 also comprises a displaydevice 340 for showing the operational status of the monitoring device330 and/or the readings of the monitored environmental parameter. Insome embodiments, the display device 340 also displays the visualizedpresentation of the monitoring results of the monitoring device 330. Inat least some embodiments, the display device 340 is an LCD monitor oran LED array.

FIG. 4 is a flow chart of a process for monitoring an environmentalparameter according to an embodiment. The flow chart is merelyexemplary, and additional functions may be performed before, after, orin between the exemplary steps. Further, in some embodiments, theexemplary functionality is performed in a different order.

In step 402, a vehicle 310 carrying a monitoring device 330 is drivenalong a predetermined route for monitoring an environmental parameter.In Step 404, position information is read from a positioning tag by aphotonic device 312 according to detection and/or scanning of thepositioning tag positioned at a predetermined position along thepredetermined route. In step 406, the environmental parameter ismonitored by a monitoring device 330 detachably mounted to the vehicle.In some embodiments, the monitoring device 330 is configured to detectvibration, temperature, humidity, contamination levels in the air,noise, bio-hazardous particles, or any combination thereof. In at leastone embodiment, the monitoring device 330 is configured to acquire stillimages or video clips.

In step 408, the monitored environmental parameter and the positioninformation are recorded by the monitoring device 330 along thepredetermined route. In some embodiments, monitoring device 330 recordsthe vibration in a time-based manner with a plurality of time tags andassociates the position information with at least one of the pluralityof time tags.

In step 410, a display device 340 or 352 displays a visualizedpresentation of the predetermined route, the recorded monitoredenvironmental parameter, and/or the recorded position information isshown by.

FIG. 5A is a chart of a recorded environmental parameter versus a timeaxis according to an embodiment. In some embodiments, when themonitoring device 330 starts to record the monitored environmentalparameter, the monitored results are recorded in a time-based manner. Inat least some embodiments, each monitored result is associated with atime tag generated by the monitoring device 330. For example, in atleast one embodiment, a vibration of the vehicle 330 is monitored by themonitoring device 330. The monitoring device 330 continuously monitorsthe vibration and associates the results with time tags. Therefore, therelation between recorded monitored vibration versus a time axis isdepicted in FIG. 5A. However, in some applications, because more thanone vehicle may move along the tracks or routes at the same time, thevehicle 310 carrying the monitoring device 330 is ordered by the trafficcontrol center to stop, speed up, or slow down from time to time. Thatis, the vehicle 310 does not necessarily travel at a constant speed.Thus, merely from the information depicted in FIG. 5A, the spatialrelationship between the recorded monitored environmental parameter andits corresponding positions along the predetermined route cannot beproperly determined.

FIG. 5B is a chart of a recorded environmental parameter versus a timeaxis in combination with recorded position information associated with aplurality of time tags according to an embodiment. In some embodiments,the monitoring device 330 also receives position information from thevehicle and associates the received position information with time tags.In some embodiments, the read position information is translated into atext code for recording. As such, the spatial relationship between therecorded monitored environmental parameter and the correspondingpositions along the predetermined route are determinable from therecorded monitored environmental parameter and the position information(such as the Position Tags #1-#4 depicted in FIG. 5B).

FIG. 6 is a diagram of an exemplary visualized presentation ofpredetermined routes with dots depicted to identify positions ofabnormality. In order to better identify the positions along thepredetermined route where abnormality is suggested by the monitoredenvironmental parameter and thus further actions may be necessary, thedisplay device 610 displays a visualization of the recorded monitoredenvironmental parameter. In at least one embodiment, the display ofvisualized presentation of the monitoring results is performed by thelog server 350 executing a program or a set of instructions stored in astorage device 356 of the log server 350.

In some embodiments, a layout of the predetermined route as well asother possible routes, such as tracks 612 a-612 g, is depicted on thedisplay device 610. At least one data point in the recorded monitoredenvironmental parameter that will be identified in the visualizedpresentation is selected. For example, if the monitored environmentalparameter is vibration of monitoring device 330 while mounted to thevehicle 310, a data point in the recorded monitored environmentalparameter having a vibration value greater than a predeterminedthreshold (such as 0.5G for example) can be selected as a selected datapoint associated with a location of an abnormal occurrence.

Further, a position on the layout of the predetermined route can beselected according to the recorded position information and the selecteddata point. Numerical calculations, such as an interpolation or anextrapolation to determine a position corresponding to the selected datapoint, are performed in order to more accurately determine the position.Then, the position corresponding to the location of abnormal occurrenceis identified on the layout of the predetermined route displayed on thedisplay device 610. Based on the visualized presentation, further actscan be taken to cure the identified abnormality. For example, if thevibration at a specific position along a track exceeds the predeterminedthreshold, a nearby track assembly, track joint or track junction isexamined, adjusted, or replaced, to ease the vibration.

In some embodiments, the recorded monitored environmental parameter isscreened by two or more threshold values. For example, when monitoringthe vibration of the vehicle along the predetermined route, a firstgroup of data points having values greater than 0.5G and a second groupof data points having values greater than 0.4G, but no greater than0.5G, are selected. Subsequently, the positions on the depicted layoutof the tracks 612 a-612 g are determined, and these positions areidentified on the display device 610 with predetermined symbols 616a-616 d and 618 a-618 b. In at least one embodiment, positionscorresponding to the first group of data points are depicted with reddots such as dots 616 a-616 d, and positions corresponding to the secondgroup of data points are depicted with yellow dots such as dots 618a-618 b. In some embodiments, instead of colored dots, the positionscorresponding to the first and second groups of data points are depictedby dots with shading or patterns, colored segments, or arrows pointingto corresponding positions on the layout of tracks 612 a-612 g.

It will be readily seen by one of ordinary skill in the art that thedisclosed embodiments fulfill one or more of the advantages set forthabove. After reading the foregoing specification, one of ordinary skillwill be able to affect various changes, substitutions of equivalents andvarious other embodiments as broadly disclosed herein. It is thereforeintended that the protection granted hereon be limited only by thedefinition contained in the appended claims and equivalents thereof.

1. A monitoring system for a wafer handling system comprising: a vehiclemovable along a predetermined route, the vehicle comprising: a photonicdevice configured to read position information according to detection ofa positioning tag positioned at a predetermined position along thepredetermined route; and a monitoring device detachably mounted to thevehicle, the monitoring device comprising: a sensor configured tomonitor an environmental parameter; and a controller communicativelycoupled to the sensor and the photonic device, the controller beingconfigured to record the monitored environmental parameter along thepredetermined route and the position information.
 2. The monitoringsystem of claim 1, wherein the environmental parameter is vibration ofthe monitoring device when mounted to the vehicle, and the sensor is avibration sensor.
 3. The monitoring system of claim 2, wherein thevibration sensor is a tri-axial vibration sensing device.
 4. Themonitoring system of claim 1, wherein the controller is configured torecord the vibration in a time-based manner with a plurality of timetags, and to associate the position information with at least one of theplurality of time tags.
 5. The monitoring system of claim 1, wherein thepositioning tag comprises an optical feature.
 6. The monitoring systemof claim 5, wherein the optical feature is a barcode, a text, a figure,or a combination thereof.
 7. The monitoring system of claim 1, furthercomprising: a display device configured to show a visualizedpresentation of the predetermined route, the recorded monitoredenvironmental parameter, and the recoded position information.
 8. Themonitoring system of claim 1, wherein the vehicle further comprises afirst communication module communicatively coupled to the photonicdevice, and the monitoring device further comprises a secondcommunication module communicatively coupled to the controller and isconfigured to communicate with the first communication module.
 9. Themonitoring system of claim 8, wherein the first communication module andthe second communication module are BLUETOOTH communication modules. 10.The monitoring system of claim 1, further comprising: a serverconfigured to receive the recorded monitored environmental parameter andthe recorded position information from the monitoring device.
 11. Amethod of monitoring an environmental parameter, comprising: driving avehicle along a predetermined route; reading, by a photonic device,position information according to detection of a positioning tagpositioned at a predetermined position along the predetermined route;monitoring an environmental parameter by a monitoring device detachablymounted to the vehicle; and recording, by the monitoring device, themonitored environmental parameter along the predetermined route and theposition information.
 12. The method of claim 11, wherein the readingposition information comprises translating an optical feature on thepositioning tag into a text code.
 13. The method of claim 11, whereinthe environmental parameter is vibration of the monitoring device whenbeing mounted to the vehicle.
 14. The method of claim 13, wherein therecording the monitored environmental parameter with the positioninginformation comprises: recording the vibration in a time-based mannerwith a plurality of time tags; and associating the position informationwith at least one of the plurality of time tags.
 15. The method of claim11, further comprising: displaying, by a display device, a visualizedpresentation of the predetermined route, the recorded monitoredenvironmental parameter, and the recorded position information.
 16. Themethod of claim 15, wherein the showing a visualized presentationcomprises: depicting a layout of the predetermined route on the displaydevice; selecting at least one data point in the recorded monitoredenvironmental parameter that will be identified in the visualizedpresentation; selecting a position on the layout of the predeterminedroute according to the recorded position information and the selected atleast one data point; and identifying the position on the layout of thepredetermined route on the display device.
 17. The method of claim 16,wherein the identifying the position on the layout of the predeterminedroute comprises: depicting a colored dot corresponds to the selectedposition on the layout of the predetermined route on the display device.18. The method of claim 16, wherein the environmental parameter isvibration of monitoring device when being mounted to the vehicle, andthe selected at least one data point has a vibration value greater thana predetermined threshold.
 19. An Automated Material Handling System(AMHS) comprising: a track; a positioning tag disposed positioned at apredetermined position along the track; and a vehicle configured tocarry a monitoring device and move along the track, the vehiclecomprising: a photonic device configured to read position informationaccording to detection of the positioning tag; and a communicationmodule communicatively coupled to the photonic device and configured totransmit the position information to the monitoring device.
 20. The AMHSof claim 19, wherein the positioning tag comprises an optical feature.